1. Field of the Invention
The present invention relates to a film clamping and cutting device of stretch wrapping machines, especially to a film clamping and cutting device of stretch wrapping machines that includes a film clamping and cutting rod and a clamp. When the film clamping and cutting rod and the clamp reach certain positions, the film clamping and cutting device clamps and cuts the film precisely.
2. Description of Related Art
Refer to Taiwanese Pat. Pub. App. No. M398517, a drag set of a film clamping and cutting device of stretch wrapping machines is revealed. In order to make the movement of a shaft of a rotatable block that drives a clamp to open and close and together with the movement of a drag plate of the drag set become smoother, a bottom edge of the drag plate is a curved sliding surface. The shaft of the rotatable block is against the curved sliding surface directly. However, when elastic fatigue of an elastic part used as an auxiliary of a drag plate occurs, the force of the drag plate acted on the shaft of the rotatable block is reduced. Thus the shaft of the rotatable block is easily sliding out from the curve sliding surface. This causes that the shaft of the rotatable block is separated from the drag plate when a film clamping and cutting rod and the clamp have not contacted and cut a film yet. Thus the clamp is closed, the film is not cut off and the residual film is not ripped off completely. Moreover, the distance between the film and objects to be wrapped is increased by a film guiding member and this is beneficial to following film cutting process performed by the film clamping and cutting rod and the clamp. However, the film guiding member including a film guiding rod and a connection rod occupies quite a lot space. The manufacturing cost is increased. These component are assembled and easily to fall off. This has negative effect on synchronous movement of the film clamping and cutting rod and the clamp.